Air-brake system for railway-trains.



PATENTED JULY 5, 1964 N. M. TIFFANY. AIR BRAKE SYSTEM FOR RAILWAY TRAINS.

APPLICATION FILED JULY 13, 1903.

N0 MODEL.

WWW

UNITED STATES Patented July 5, 1904..

PATENT AIR-BRAKE SYSTEM FOR RAILWAY-TRAINS.

SPECIFICATION forming part of- Letters Patent No. 764,217, dated July 5, 1904.

Application filed July 13, 1903. Serial No. 165,277. (No model.)

To aJZ whom, it nut/y concern;

Be it known that I, NELSON M. TIFFANY, of Syracuse, in the county of Onondaga, in the State of New York, have invented new and useful Improvements in Air-Brake Systems for Railway-Trains, of which the following,

taken in connection with the accompanying drawings, is a full, clear, and exact description.

ments in automatic air-brake systems, and is particularly applicable for use in connection with long trains, such as freight-trains, in which the engine and tender, as well as the several cars, are each equipped with an automatic air-brake and operating mechanism. This system implies the use of a main storagereservoir for the compressed air and an engineers brake-valve, both of which are located on the engine, the air being compressed in the mam reservoir by suitable steamoperated pumps, and its passage to the train-pipe is regulated by the engineers valve, which is located in the engine-cab in convenient proximity to the engineer.

The brake-operating mechanism consists, essentially, of a triple valve, an auxiliary air-reservoir, and a brake-cylinder, in which latter is movable a suitable piston for actuating the brake-shoes.

The triple valve of each car is connected directly to the main pipe, and its function is to admit and to maintain compressed air in the auxiliary reservoirs and when the pressure in the train-pipe is reduced from any cause to permit the compressed air to flow from the auxiliary reservoirs into their respective brake-cylinders to actuate the brake, and when the full normal pressure is again restored in the train-pipe the air is automatically released from the brake-cylinders to at mosphere to release the brakes.

The reduction and restoration of air-pressure in the train-pipes is under normal conditions controlled by the engineers brake-valve; but it is apparent that if this pressure should be reduced by leakage or a break in the trainpipe the brakes would be set automatically in the same manner as if purposely reduced by the operation of the engineers valve.

This invention relates to certain improve- I have thus far briefly described a wellknown air-brake system for the purpose of clearly demonstrating the effect of its operation upon a long train of cars.

Assuming now that a train is running at the usual speed and it becomes necessary from any cause to suddenly slacken the speed by applying the brakes, in this instance it is apparent that, owing to the position of the engineers valve at the head of the train, the pressure in the train-pipe begins to reduce at points nearest to the valve, and therefore first causes the operation of the brakes of the engine and tender and then causes the successive operation of the brakes of the remaining cars, according to their distances from the engineers valve.

This causes a gradual compression of the train and draw-heads of the cars by reason of the momentum of the train and the retardationof the ears successively from front to rear.

In a large majority of instances the application of the brakes is only for the purpose of slackening the speed of the train, after which the brakes are released before the train comes to a full stop. In such instances it is obvious that the drawbars of the ears thro ughout the train are compressed against the action of their springs, and the combined power thus stored up in these springs is of course very considerable and somewhat proportionate to the speed and length of the train and grip of the shoes when the brakes are set. Now when the brakes of the several ears, including those of the engine and tender, are re leased it is evident that the combined force of the reaction of the draw-head springs is equal to the power required to compress them and frequently acquires sul'iicient power or force to break the train in two, either by breaking the coupling or by pulling the draw-heads from their anchors. These operations of compression and distention of the train are practically instantaneous; but the accumulated and reactionary force in either case is produced successively from car to car from front to rear of the train, and it is this multiplied reactionary force which frequently breaks the train in two.

The object of my invention is to minimize this reactionary effect, and to thereby obviate the primary cause of a large percentage of the breaks in the trains by holding the engine back upon the train while the brakes on the remaining cars are released.

Other objects will be brought out in the subsequent description. 7

In the drawings, Figure 1 is a diagrammatic View of a portion of an air-brake system for the engine, tender, and one car of a freighttrain, showing the application of my invention thereto. Fig. 2 is an elevation, partly in section, of the triple valves of the engine and tender, showing my invention as connected to the air-release openings of said valves. Figs. 3, 1, and 5 are detail sectional views of the detached release-valve in different positions.

Similar reference characters indicate corresponding parts in all the views.

The air-brake system shown in Fig. 1 exclusive of my improvement is of the ordinary Westinghouse automatic quick-action type, such as is commonly used on freight-trains, i and consists, essentially, of a train or service i pipe 1, to which are connected an engineers brake-valve 2 and a series of triple valves 3, one of the latter for each car, including the; engine and tender. Connected to each of these triple valves are the'usual auxiliary airreservoir 4: and brake-cylinder 5, and it is now apparent that the engine, tender, and each of the cars are equipped with a brake-operating mechanism consisting of a triple valve, an auxiliary air-reservoir and a brakecylinder, which are connected to the main service-pipe. This service-pipe is in turn connected to a? suitable main reservoir, (not shown,) but i which is located as usual upon the engine and i. is supplied with compressed air from suitable steam-pumps, also on the engine, but not illustrated.

The train-pipe 1 is made up of a series of i car-sections, which are normally united by flexible couplings 6 between the cars and :are equipped with suitable valves, so that any one of the cars may be cut out of the train when I desired without eifecting the operation of the brake mechanism of the other cars.

Each of the brake-cylinders is provided with a piston which is connected in the usual manner to suitable brake-shoes on the car; but I f have shown such brake-shoes only on the en- 1 gine, it being understood that the pistons of the brake-cylinders of the tender and cars are connected in the Well-known manner to their respective brake mechanisms.

The operation of the above-described system is believed to be well understood, and it is therefore necessary to refer only briefly to such operation, which is as follows: Assuming that the brakes are released and that the engineers valve is set to the running position, in which the train-pipe is open from the main reservoir to maintaln a certain air-pressure in the train-pipe and auxiliary reservoirs of the engine and tender and of the several cars as governed by the triple valves, now when it is desired to apply the brakes the engineers valve is operated to reduce the pressure in the train-pipe, which causes the automatic action of the triple valves to permit the passage of compressed air from the auxiliary reservoirs to theirrespective brake-cylinders to actuate their brakes. To release the brakes, the engineers valve is returned, and the air again assumes normal pressure in the trainpipe, whereupon the equalization of the pressure in said pipe and auxiliary reservoirs operates the triple valve to permit the air to escape from the brake-cylinders of all of the cars, including the engine and tender, to atmosphere, so that the brake-operating pistons may return to their normal positions and release the brakes. It is well known that these triple valves are provided with air-passages 7, which open to atmosphere, and that these openings are only brought into communication with the brake-cylinders when the brakes are released. I It is at this period of release of the brakes and escape of compressed air from the brake-cylinder to atmosphere that my present invention comes into use to prevent too great a recoil or reaction of the compressed draw-head springs, which tends to break the train in two. This reaction is reduced to a safe degree by preventing the release of the air-brakes of the engine or tender, or both, as shown, when the brakes of the remaining cars of the train are released, so that the head end of the train is held back, and thereby eases off the rapid and powerful reaction from front to rear of the train. This is accomplished by a suitable auxiliary engineers valve 8, which is connected by conduits 9 and 10 to the vent-openings 7 of the triple valves of the engine and tender, whereby the compressed air in the brake-cylinders of the engine and tender is held from escaping to atmosphere at the will of the engineer or until he is satisfied that the reaction is substantially spent, and then he may operate the valve 8 to release either the tender or engine brakes, or

' both simultaneously,if desired.

In Figs. 3, 4, and 5 the case of the valve 8 is shown as provided with three ways 11, 12, and 13, while therotary part is provided with ways 14:, 15, and 16. The ways 11 and 14 open to atmosphere, and the ways 12 and 13 are connected, respectively, to the conduits 9 and 10, while the passage or ways 15 and 16 are movable into and out of registration with the passages 12 and 13, respectively. It is now seen that the vent-openings of the triple valves of the engine and tender are connected to each other with the valve 8 in the connection, so that after the brakes of the several cars, except those of the engine and tender, are released the valve 8 may remain closed to prevent the escape of air from the triple valves of said engine and tender and to thereby prevent the release of their brakes until the engineer is assured that the force of the reaction of the draw-head springs is substantially spent, whereupon he may open one or both ports of the valve 8 to atmosphere and permit the release of the brakes thus controlled.

Having thus described my invention, what I claim, and desire to secure by Letters Patent,

1. In an automatic air-brake system, the combination with a train-pipe and an engineers valve, of two triple valves connected to the train-pipe and having air-vents connected to each other, and an auxiliary valve in the tender and carsot' a train, each mechanism comprising a brake-cylinder and an auxiliary reservoir and a triple valve having an air-vent for its brake-cylinder, a separate conduit connecting the vent of the triple valves of the engine and tender, and an auxiliary valve in the engine connectedin said conduit to control the air-release from the triple valves of the engine and tender for controlling the action of their brakes independently of the engineers valve.

3. In combinationwith atrain-pipe and separate brake-operating mechanisms for the engine and tender and for the several cars of a train, each mechanism including a brakecylinder and triple valve having an air-vent for the brake-cylinder, an engineers valve connected in the train-pipe to control the air-pressure in the train-pipe, a separate conduit connecting the air-vents of the triple valves of the engine and tender, and a separate engineers valve in the engine connected in said conduit to control the escape of air from the triple valves of the engine and tender independently of the engineers valve.

In Witness whereof I have hereunto set my hand this 1st day of July, 1903.

NELSON M. TIFFANY.

Witnesses:

H. E. CHASE, MILDRED M. NOTT. 

